ENERGY giant Drax has said it is seeking official approval for a massive expansion of the “Hollow Mountain” hydro power plant in Argyll though a development it expects would create 900 jobs in the area.

The company wants to build a second power station at the Cruachan pumped storage hydro plant, which would more than double its capacity.

The proposed expansion would involve creating a second huge turbine hall inside Ben Cruachan. The turbines would be driven by water that would be allowed to flow from a reservoir in the hills to Loch Awe below.

The decision to initiate the approval process underlines Drax’s belief in the potential of a project that it reckons could provide important support for the drive to reduce emissions.

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The additional capacity at Cruachan could be used to allow the plant to store electricity generated by windfarms and the like at times of low demand.

Chief executive Will Gardiner said: “Last year, the UK’s lack of energy storage capacity meant wind farms had to be paid to turn off and we lost out on enough renewable power to supply a million homes.

“We need to stop renewable power from going to waste by storing it, and Drax is ready to move mountains to do just that.”

Drax made clear it would expect the UK Government to help ensure that it could generate the required return on the investment that would be involved. The bill could run into hundreds of million of pounds.

The Yorkshire-based company said the project would require an updated policy and market support mechanism from the UK Government.

It noted that no new pumped storage hydro plants had been built in the UK since 1984 “despite their critical role in decarbonisation”.

HeraldScotland: How the new Cruachan plant would work Image: DraxHow the new Cruachan plant would work Image: Drax

Drax would require Scottish Government approval for the proposed expansion of Cruachan, under Section 36 of the Electricity Act 1989.

It will launch a public consultation next week and expects to submit an Environmental Impact Assessment Scoping Report to the Scottish Government imminently.

Cruachan was opened in 1965. The reversible turbines at the plant allow water to be pumped from Loch Awe to the reservoir above at times of low demand. Loch Awe serves as a second reservoir.

Drax acquired Cruachan with a portfolio containing other assets in Scotland from ScottishPower in a £700 million deal in 2018.

The company said the new cavern it plans to create would be large enough to fit Big Ben on its side. It would be built to the east of the existing one. More than a million tonnes of rock would be excavated to create the cavern and other parts of the power station.

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If approved the 600MW power station would increase the site’s total capacity to 1.04GW.

Brendan O’Hara, Scottish National Party MP for Argyll & Bute, said he was delighted that Drax is progressing plans to expand the Ben Cruachan site.

He noted: "This will support 900 rural jobs and create a pumped storage facility that will be able to provide enough renewable energy to power a million homes while helping us reach our 2045 net zero target, it is great news for this area and for Scotland.”